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The PharmGKB's clinical annotations reflect expert consensus based on clinical evidence and peer-reviewed
literature available at the time they are written and are intended only to assist clinicians in decision-making
and to identify questions for further research. New evidence may have emerged since the time an annotation was
submitted to the PharmGKB. The annotations are limited in scope and are not applicable to interventions or
diseases that are not specifically identified.

The annotations do not account for individual variations among patients, and cannot be considered inclusive of all
proper methods of care or exclusive of other treatments. It remains the responsibility of the health-care provider
to determine the best course of treatment for a patient. Adherence to any guideline is voluntary, with the
ultimate determination regarding its application to be made solely by the clinician and the patient. PharmGKB
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The table below contains information about pharmacogenomic variants on PharmGKB. Please follow the link in the
"Variant" column for more information about a particular variant. Each link in the "Variant" column leads to the
corresponding PharmGKB Variant Page. The Variant Page contains summary data, including PharmGKB manually curated
information about variant-drug pairs based on individual PubMed publications. The PMIDs for these PubMed publications
can be found on the Variant Page.

The tags in the first column of the table indicate what type of information can be found on the corresponding
Variant Page.

Description

The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Acetylsalicylic acid also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. (From Martindale, The Extra Pharmacopoeia, 30th ed, p5)

Source: Drug Bank

Indication

For use in the temporary relief of various forms of pain, inflammation associated with various conditions (including rheumatoid arthritis, juvenile rheumatoid arthritis, systemic lupus erythematosus, osteoarthritis, and ankylosing spondylitis), and is also used to reduce the risk of death and/or nonfatal myocardial infarction in patients with a previous infarction or unstable angina pectoris.

Pharmacology, Interactions, and Contraindications

Mechanism of Action

The analgesic, antipyretic, and anti-inflammatory effects of acetylsalicylic acid are due to actions by both the acetyl and the salicylate portions of the intact molecule as well as by the active salicylate metabolite. Acetylsalicylic acid directly and irreversibly inhibits the activity of both types of cyclooxygenase (COX-1 and COX-2) to decrease the formation of precursors of prostaglandins and thromboxanes from arachidonic acid. This makes acetylsalicylic acid different from other NSAIDS (such as diclofenac and ibuprofen) which are reversible inhibitors. Salicylate may competitively inhibit prostaglandin formation. Acetylsalicylic acid's antirheumatic (nonsteroidal anti-inflammatory) actions are a result of its analgesic and anti-inflammatory mechanisms; the therapeutic effects are not due to pituitary-adrenal stimulation. The platelet aggregation-inhibiting effect of acetylsalicylic acid specifically involves the compound's ability to act as an acetyl donor to cyclooxygenase; the nonacetylated salicylates have no clinically significant effect on platelet aggregation. Irreversible acetylation renders cyclooxygenase inactive, thereby preventing the formation of the aggregating agent thromboxane A2 in platelets. Since platelets lack the ability to synthesize new proteins, the effects persist for the life of the exposed platelets (7-10 days). Acetylsalicylic acid may also inhibit production of the platelet aggregation inhibitor, prostacyclin (prostaglandin I2), by blood vessel endothelial cells; however, inhibition prostacyclin production is not permanent as endothelial cells can produce more cyclooxygenase to replace the non-functional enzyme.

Source: Drug Bank

Pharmacology

Acetylsalicylic acid is an analgesic, antipyretic, antirheumatic, and anti-inflammatory agent. Acetylsalicylic acid's mode of action as an antiinflammatory and antirheumatic agent may be due to inhibition of synthesis and release of prostaglandins. Acetylsalicylic acid appears to produce analgesia by virtue of both a peripheral and CNS effect. Peripherally, acetylsalicylic acid acts by inhibiting the synthesis and release of prostaglandins. Acting centrally, it would appear to produce analgesia at a hypothalamic site in the brain, although the mode of action is not known. Acetylsalicylic acid also acts on the hypothalamus to produce antipyresis; heat dissipation is increased as a result of vasodilation and increased peripheral blood flow. Acetylsalicylic acid's antipyretic activity may also be related to inhibition of synthesis and release of prostaglandins.

Source: Drug Bank

Food Interaction

Avoid alcohol, alcohol appears to cause a 50 to 100% increases in ASA serum levels.|Take with food to reduce gastric irritation.|Take with a full glass of water.

Source: Drug Bank

Absorption, Distribution, Metabolism, Elimination & Toxicity

Biotransformation

Acetylsalicylic acid is rapidly hydrolyzed primarily in the liver to salicylic acid, which is conjugated with glycine (forming salicyluric acid) and glucuronic acid and excreted largely in the urine.

Source: Drug Bank

Protein Binding

High (99.5%) to albumin. Decreases as plasma salicylate concentration increases, with reduced plasma albumin concentration or renal dysfunction, and during pregnancy.

Source: Drug Bank

Absorption

Absorption is generally rapid and complete following oral administration but may vary according to specific salicylate used, dosage form, and other factors such as tablet dissolution rate and gastric or intraluminal pH.

Source: Drug Bank

Half-Life

The plasma half-life is approximately 15 minutes; that for salicylate lengthens as the dose increases: doses of 300 to 650 mg have a half-life of 3.1 to 3.2 hours; with doses of 1 gram, the half-life is increased to 5 hours and with 2 grams it is increased to about 9 hours.

Genes that are associated with this drug in PharmGKB's database based on (1) variant annotations, (2)
literature review, (3) pathways or (4) information automatically retrieved from DrugBank, depending on
the "evidence" and "source" listed below.

Concomitant therapy of the NSAID, ketoprofen, and acetylsalicylic acid may result in additive adverse/toxic effects (e.g. GI bleeding). The NSAID may also limit the cardioprotective effect of acetylsalicylic acid. Occasional concomitant use may not cause clinically significant problems, but regular, frequent concomitant therapy is not recommended.
(source: Drug Bank)